Method for regulating and controlling browning of fruit juice by combining vacuum ultrasound and high-pressure CO2 and control system thereof

Abstract

The invention provides a vacuum ultrasound-high pressure CO2 combined fruit juice browning regulation and control method and a control system thereof, and relates to an agricultural product deep processing technology. In the enzymolysis step, the fruit juice is subjected to ultrasonic treatment at a low temperature, the nutritional ingredients of the fruit juice are increased, browning is reduced, and enzymolysis is further promoted through compatibility of a mixed enzyme preparation; in the enzyme deactivation and sterilization step, high-pressure CO2 is introduced into the juice containing ultrasonic vacuum, and the CO2 easily enters the ultrasonic vacuum, so that the CO2 is better combined with bacteria for sterilization, and the sterilization effect is improved; the low temperature is maintained in the enzyme deactivation and sterilization step, so that the loss of active substances can be effectively reduced, and browning can be reduced.

Description

Technical Field

[0001] The invention relates to a deep processing technology for agricultural products, and in particular to a method for vacuum ultrasound-high pressure CO2 combined regulation of fruit juice browning and a control system thereof. Background Art

[0002] Juice contains many bioactive compounds, such as fresh roxburghii fruit, which is rich in tannins, vitamin C, polyphenols, amino acids, superoxide dismutase (SOD) and other functional ingredients. Among them, highly sensitive nutrients in juice, such as vitamins, are absorbed by oxygen during the extraction and processing of juice. The dissolved oxygen concentration in the solution is high. In the presence of metal ions and oxygen, high temperature (> 60°C) will degrade vitamins, reduce nutritional value, and accelerate the browning process.

[0003] In traditional thermal processing, ultraviolet sterilization or high-pressure and high-temperature sterilization treatment is still the most widely used technology for inactivating microorganisms in juice production. CN202123201924.2 discloses a juice sterilization device, including a tank body, a tank cover is provided on the top of the tank body, a mounting groove is provided in the middle of the tank cover, an ultraviolet lamp assembly is nested in the mounting groove, and the ultraviolet lamp assembly includes a mounting seat, and an ultraviolet lamp post is provided in the middle of the lower side of the mounting seat. The outer side of the ultraviolet lamp post is sleeved with an insulating transparent cylinder, and the insulating transparent cylinder penetrates the mounting groove and extends into the tank body. The tank body includes an outer shell and an inner shell, and an insulation layer is filled between the inner shell and the outer shell. Grooves are provided on the front, back, left and right sides of the lower inner side of the insulation layer, and a heating pipe is provided inside the groove. The inner wall of the inner shell is set as a diamond mirror. The utility model processes the juice of the tank body through the heating pipe to achieve high-temperature sterilization. At the same time, the ultraviolet lamp post emits ultraviolet rays through the insulating transparent cylinder to sterilize the juice with ultraviolet rays. High-temperature sterilization and ultraviolet sterilization cooperate with each other for sterilization, and sterilization is more thorough.

[0004] However, during the thermal processing, the long-term high temperature and ultraviolet rays can easily cause the juice to turn brown, the nutrients to degrade, and the production of odorous components. Summary of the invention

[0005] The purpose of the present invention is to provide a method for jointly regulating the browning of fruit juice by vacuum ultrasound and high-pressure CO2. Another purpose of the present invention is to provide a control system for regulating the browning of fruit juice. The ultrasound used in the present application can generate shock waves and high shear force, promote enzymatic hydrolysis, and thus increase the biological activity content. The combination of ultrasound, high-pressure CO2 and / or medium and low-speed stirring can improve the enzymatic hydrolysis efficiency of the fruit juice and complete sterilization at a lower temperature and in a shorter time, thereby better preserving the active ingredients of the fruit juice and reducing the occurrence of browning of the fruit juice.

[0006] In the first aspect, the present application provides a method for vacuum ultrasound-high pressure CO2 combined regulation of juice browning:

[0007] The method for vacuum ultrasound-high pressure CO2 combined regulation of juice browning comprises the following preparation steps:

[0008] Enzymolysis: adding a mixed enzyme preparation to the juice for enzymolysis treatment, subjecting the juice to ultrasonic treatment, with a maximum ultrasonic pressure range of 400-500 kPa / min, and stirring and homogenizing at a low speed to obtain an enzymolysis solution, wherein the temperature range of the enzymolysis solution is 30-42°C;

[0009] Enzyme inactivation and sterilization: After the enzymatic hydrolyzate is homogenized by vacuum ultrasonic wave, high-pressure carbon dioxide gas is introduced into the solution for high-pressure sterilization, and the pressure is maintained at 4-8 MPa. The temperature of the juice is 10-40° C. to obtain the finished product.

[0010] When ultrasonic treatment of juice in enzymatic hydrolysis, different modes of action of ultrasound and stirring, different mechanical action directions, better destroy cell walls, free radical generation and enzyme activation, while ultrasonic vacuum can more effectively reduce the dissolved oxygen content in juice than ultrasound, while maintaining low temperature, minimizing the loss of active ingredients. Ultrasonic vacuum effectively removes most of the dissolved oxygen and reduces the oxygen in the top space of the equipment. The reduction in oxygen content effectively reduces the degradation of active substances and inhibits browning. At the same time, the mixed enzyme preparation further promotes enzymatic hydrolysis.

[0011] In the enzyme inactivation and sterilization step, ultrasonic vacuum is more evenly distributed in the juice after ultrasonic treatment. High-pressure CO2 is introduced into the juice containing ultrasonic vacuum, and CO2 can easily enter the ultrasonic vacuum, thereby better combining CO2 with bacteria to sterilize, thereby improving the sterilization effect; maintaining a lower temperature in the enzyme inactivation and sterilization step can more effectively reduce the loss of active substances and reduce browning.

[0012] Furthermore, in the enzymatic hydrolysis step, the stirring speed is 150-200 r / min, and the stirring homogenization time is 30-50 min.

[0013] Furthermore, the maximum ultrasonic action time is 30-60 minutes.

[0014] Furthermore, the mixed enzyme preparation used in the enzymatic hydrolysis step includes a combination of one or more of pectinesterase, cellulase, and alcohol dehydrogenase; the enzymatic hydrolysis time is 30-60 minutes, and the concentration of the mixed enzyme preparation in the juice is 0.3-0.5 mg / mL.

[0015] Furthermore, the mixed enzyme preparation used in the enzymatic hydrolysis step is pectin esterase and cellulase in a mass ratio of (1-2):2.

[0016] The highly antioxidant pectinesterase combined with cellulase can better maintain enzyme activity and thus enhance the enzymatic hydrolysis effect.

[0017] Furthermore, the mixed enzyme preparation used in the enzymatic hydrolysis step is pectin esterase, cellulase, and alcohol dehydrogenase in a mass ratio of 2:2:(0.3-1.5).

[0018] In an ultrasonic environment, the oxygen content is low, the protein decomposition efficiency is low, and the increase in alcohol content in the enzymatic hydrolysis system will inhibit enzymatic hydrolysis. Alcohol dehydrogenase is used in combination with pectinesterase and cellulase to reduce the alcohol in the enzymatic hydrolysis system, promote the enzymatic hydrolysis effect, and increase the active ingredients in the finished product.

[0019] Furthermore, in the enzyme inactivation and sterilization step, the high pressure sterilization time is maintained for 3-10 minutes.

[0020] Furthermore, the pressure in the enzyme inactivation and sterilization step is 7-8 MPa; the temperature of the juice in the enzyme inactivation and sterilization step is 30-40°C.

[0021] Furthermore, the enzymatic solution is stirred in the enzyme inactivation and sterilization step, and the stirring speed is 150-200r / min.

[0022] In a second aspect, the present application provides a control system for regulating juice browning:

[0023] A control system for regulating browning of juice, which is applied to a method for regulating browning of juice by vacuum ultrasound-high pressure CO2;

[0024] The control system includes

[0025] A sealed jar with a stirrer,

[0026] An ultrasonic transducer connected to a sealed tank for ultrasonically vibrating the liquid in the sealed tank.

[0027] Pipeline,

[0028] The carbon dioxide storage tank is connected to the sealed tank through a pipeline.

[0029] A control valve installed on the pipeline to control the opening and closing of the pipeline.

[0030] A low-temperature cooling tank installed on the pipeline to cool the carbon dioxide in the pipeline.

[0031] and a booster pump arranged on the pipeline for increasing the pressure of carbon dioxide.

[0032] The present invention proposes a non-thermal sterilization technology, a vacuum ultrasound-high pressure CO2 combined action, a non-thermal technology that has a greater retention of bioactive substances in the food matrix while having minimal detrimental effects on the sensory appeal of the food.

[0033] When performing the enzymatic hydrolysis process, the mixed enzyme requires a specific and appropriate medium temperature. The tank body in the present invention is a three-layer tank, which can circulate hot water to heat up, and can be used as a refrigerant, which can control the temperature more accurately. The external carbon dioxide device, the carbon dioxide in the carbon dioxide device can be used as a refrigerant. The refrigerant mainly achieves the refrigeration effect through the mutual conversion between liquid and gas, and carbon dioxide can also be converted between gas and solid. Solid carbon dioxide is dry ice, which can absorb a large amount of heat during sublimation, and can realize the refrigeration cycle and low-temperature temperature control, so that sterilization can be carried out at a lower temperature; and CO2 refrigerant is non-toxic, non-flammable, has an ozone depletion potential of 0, and a global warming potential of 1, which is environmentally friendly. CO2 has a small molecular weight and a large refrigeration capacity. The unit refrigeration capacity at 0°C is 5-8 times higher than that of conventional refrigerants.

[0034] The process of the present invention can make sterilization more thorough and improve sterilization efficiency.

[0035] The control system for regulating the browning of juice can work continuously, overcoming the problem that traditional heating cannot sterilize continuously. When the juice cannot be filled in time after sterilization, the temperature can be lowered to 0-4°C. The entire equipment can be used as a sterile tank to temporarily store materials.

[0036] Beneficial effects:

[0037] 1. In the enzymatic hydrolysis step, the present application ultrasonically treats the juice while maintaining a relatively low temperature, thereby improving the nutritional content of the juice and reducing browning, and combining a mixed enzyme preparation to further promote enzymatic hydrolysis; in the enzyme inactivation and sterilization step, high-pressure CO2 is introduced into the juice containing an ultrasonic vacuum, and the CO2 easily enters the ultrasonic vacuum, thereby better combining the CO2 with the bacteria for sterilization, thereby improving the sterilization effect; maintaining a relatively low temperature in the enzyme inactivation and sterilization step can more effectively reduce the loss of active substances and reduce browning.

[0038] 2. Optimize the ultrasonic rising rate, the final ultrasonic pressure range and the stirring rate of the enzymatic hydrolysis step, control the temperature of the juice and improve the enzymatic hydrolysis effect, thereby increasing the content of active ingredients in the finished juice and reducing browning.

[0039] 3. Preferably, the type and amount of the mixed enzyme preparation enable the mixed enzyme preparation to better adapt to the enzymatic hydrolysis temperature and ultrasonic action during the enzymatic hydrolysis process, and the enzyme preparation and ultrasonic wave cooperate with each other, thereby improving the enzymatic hydrolysis effect and the content of active ingredients in the finished fruit juice.

[0040] 4. Stir the enzymatic solution during the enzyme inactivation and sterilization step to allow CO2 to better enter the ultrasonic vacuum in the juice, promote the uniform distribution of CO2 in the juice and enhance the combination of CO2 and bacteria, thereby improving the sterilization effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1It is the control system for regulating juice browning adopted in the present invention / Example 1.

[0042] Reference numerals:

[0043] 1. Feed inlet; 2. Liquid level tube; 3. Sealed tank; 4. Stirring paddle; 5. Discharge port; 6. Motor; 7. Ultrasonic transducer; 8. Rotating shaft; 9. Vacuum instrument; 10. Carbon dioxide storage tank; 11. Air inlet; 12. Control valve; 13. Filter; 14. Low-temperature cooling tank; 15. Thermometer; 16. Booster pump; 17. Booster pump pressure gauge; 18. Aseptic sampling valve; 19. Pre-tightening bolt; 20. Rear driver; 21. Piezoelectric ceramics; 22. Radiator; 23. Front driver; 24. Connecting screw hole. DETAILED DESCRIPTION

[0044] In order to make the technical solution of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0045] Example 1, a method for regulating juice browning by vacuum ultrasound-high pressure CO2:

[0046] The control system used to regulate juice browning includes

[0047] A sealed tank 3 containing a stirrer,

[0048] An ultrasonic transducer 7 connected to the sealed tank 3 for ultrasonically vibrating the liquid in the sealed tank 3,

[0049] Pipeline,

[0050] The carbon dioxide storage tank 10 is connected to the sealed tank 3 through a pipeline,

[0051] A control valve 12 is provided on the pipeline to control the opening and closing of the pipeline.

[0052] A low temperature cooling tank 14 is provided on the pipeline for cooling the carbon dioxide in the pipeline.

[0053] and a booster pump 16 disposed on the pipeline for increasing the pressure of carbon dioxide;

[0054] And a filter 13, a thermometer 15, a booster pump 16 and a booster pump pressure gauge 17 arranged on the pipeline.

[0055] The ultrasonic transducer 7 includes a pre-tightening bolt 19 , a rear driver 20 , a piezoelectric ceramic 21 , a heat sink 22 , a front driver 23 and a connecting screw hole 24 .

[0056] The stirrer includes a stirring paddle 4 , a rotating shaft 8 and a motor 6 .

[0057] The sealed tank 3 is provided with a liquid level tube 2, a sterile sampling valve 18, a feed inlet 1 and a discharge port 5, and the tank body of the sealed tank 3 is a three-layer structure.

[0058] Working principle of the equipment: the juice obtained after washing and squeezing the fruit flows through the sealed tank 3, the sealed tank 3 is externally connected to the ultrasonic transducer 7, the ultrasonic transducer 7 converts the internal environment of the tank into a vacuum, and at the same time turns on the stirring paddle 4 to stir the material evenly. The mechanical effect of the vacuum ultrasound causes cavitation of the juice, resulting in the rupture of high-pressure bubbles, which damages the cell wall, releases intracellular compounds, and increases the amount of bioactive substances, such as flavonoids and vitamin C.

[0059] The external liquid level tube 2 displays the liquid level of the material in the tank; the carbon dioxide storage tank 10 stores gaseous carbon dioxide, and the filter 13 cools and liquefies the gaseous carbon dioxide in the low-temperature cooling tank 14, and is connected to the booster pump 16 to compress the liquid carbon dioxide into high-pressure carbon dioxide. Carbon dioxide is passed into the material tank through the filter 13, the cooling tank, and the booster pump 16. The vacuum ultrasonic and enzymatic hydrolysis process is used to improve the quality and biological activity of the product, and high-pressure carbon dioxide is passed in for high-pressure sterilization. The low-temperature sterilization method - high-pressure carbon dioxide, retains the biologically active substances of the juice to the greatest extent and enhances the sterilization efficiency.

[0060] A method for vacuum ultrasound-high pressure CO2 combined regulation of juice browning, comprising the following preparation steps:

[0061] Cleaning and squeezing: fully mature, non-moldy fresh roxburghii fruits are cleaned with a cleaning machine, and mechanically squeezed and filtered to obtain roxburghii juice;

[0062] Enzymolysis: The juice is pumped into the aforementioned sealed tank, and a mixed enzyme preparation (the mixed enzyme preparation adopts a combination of pectinesterase and cellulase in a mass ratio of 1:2) is added to the juice for enzymolysis treatment, and the concentration of the mixed enzyme preparation in the juice is 0.4 mg / mL; the sealed tank is connected to an ultrasonic transducer, and the ultrasonic pressure slowly increases at a rate of 85±5 kPa / min. At a frequency of 30 kHz and an output power of 500 W, the maximum ultrasonic pressure is 450 kPa / min, and the treatment is 8 minutes; at the same time, the stirring paddle is stirred at 180 r / min, the enzymolysis time is 50 minutes, and an enzymolysis solution is obtained, and the temperature of the enzymolysis solution is 35°C.

[0063] Enzyme inactivation and sterilization: After the enzymatic hydrolysate is treated with vacuum ultrasonic homogenization, the pressure in the sealed tank is maintained at 7MPa, and high-pressure carbon dioxide gas is introduced into the solution for high-pressure sterilization. The temperature of the juice is 35°C; the gas pressure introduced into the pipeline is 75±0.5MPa; the high-pressure sterilization time is maintained for 6 minutes to obtain the finished product.

[0064] Packaging and storage: Collect the sterilized sea buckthorn juice in a sterile container and store it in a refrigerator at 2±2℃.

[0065] Example 2, a method for jointly regulating browning of fruit juice by vacuum ultrasound and high-pressure CO2, is different from Example 1 in that a different preparation process is used, as shown in Table 1.

[0066] Table 1. List of parameter settings in the method for vacuum ultrasound-high pressure CO2 combined regulation of juice browning in Examples 1 to 3

[0067]

[0068]

[0069] Example 4, a method for jointly regulating fruit juice browning by vacuum ultrasound and high-pressure CO2, differs from Example 1 in that the mixed enzyme preparation uses pectinesterase and cellulase in a mass ratio of 0.5:2.

[0070] Example 5, a method for jointly regulating browning of fruit juice by vacuum ultrasound and high-pressure CO2, is different from Example 1 in that the mixed enzyme preparation uses cellulase.

[0071] Example 6, a method for jointly regulating fruit juice browning by vacuum ultrasound and high-pressure CO2, differs from Example 1 in that the mixed enzyme preparation adopts a combination of pectinesterase, cellulase and alcohol dehydrogenase in a mass ratio of 2:2:0.1.

[0072] Example 7, a method for jointly regulating fruit juice browning by vacuum ultrasound and high-pressure CO2, differs from Example 1 in that the mixed enzyme preparation adopts a combination of pectinesterase, cellulase and alcohol dehydrogenase in a mass ratio of 2:2:0.3.

[0073] Example 8, a method for jointly regulating fruit juice browning by vacuum ultrasound and high-pressure CO2, differs from Example 1 in that the mixed enzyme preparation adopts a combination of pectinesterase, cellulase and alcohol dehydrogenase in a mass ratio of 2:2:1.

[0074] Example 9, a method for jointly regulating fruit juice browning by vacuum ultrasound and high-pressure CO2, differs from Example 1 in that the mixed enzyme preparation adopts a combination of pectinesterase, cellulase and alcohol dehydrogenase in a mass ratio of 2:2:1.5.

[0075] Example 10, a method for jointly regulating fruit juice browning by vacuum ultrasound and high-pressure CO2, differs from Example 1 in that the mixed enzyme preparation adopts a combination of pectinesterase, cellulase and alcohol dehydrogenase in a mass ratio of 2:2:2.

[0076] Example 11, a method for jointly regulating browning of fruit juice by vacuum ultrasound and high-pressure CO2, is different from Example 1 in that the pressure in the enzyme inactivation and sterilization step is 6 MPa; the temperature of the fruit juice in the enzyme inactivation and sterilization step is 46°C.

[0077] Example 12, a method for jointly regulating browning of fruit juice by vacuum ultrasound and high-pressure CO2, differs from Example 1 in that the enzymatic hydrolyzate is stirred during the enzyme inactivation and sterilization step, and the stirring speed is 180 r / min.

[0078] Example 13, a method for jointly regulating browning of fruit juice by vacuum ultrasound and high-pressure CO2, differs from Example 11 in that the enzymatic hydrolyzate is stirred during the enzyme inactivation and sterilization step, and the stirring speed is 180 r / min.

[0079] Comparative Example 1, a method for jointly regulating browning of fruit juice by vacuum ultrasound and high-pressure CO2, differs from Example 1 in that the temperature range of the enzymatic hydrolysis solution in the enzymatic hydrolysis step is 45°C, the stirring speed is 500r / min; and the pressure is maintained at 2.2MPa in the enzyme inactivation and sterilization step.

[0080] Comparative Example 2, a method for jointly regulating browning of fruit juice by vacuum ultrasound and high-pressure CO2, differs from Example 1 in that, in the enzyme inactivation and sterilization step, the pressure is maintained at 3 MPa and the temperature of the fruit juice is maintained at 45°C.

[0081] Comparative Example 3, a method for controlling the browning of juice by vacuum ultrasound-high pressure CO2, which is different from Example 1 in that the enzyme inactivation and sterilization adopts ordinary sterilization (pasteurization) to treat the juice after enzymolysis;

[0082] The specific operation is to adjust the temperature of the enzymatically hydrolyzed juice to 70°C and treat it for 30 minutes.

[0083] Comparative Example 4, a method for controlling the browning of juice by vacuum ultrasound-high pressure CO2, is different from Example 1 in that the enzyme inactivation and sterilization adopts ordinary sterilization (pasteurization and irradiation sterilization) to treat the juice after enzymolysis;

[0084] The specific operation is to adjust the temperature of the juice after enzymatic hydrolysis to 70°C and treat it for 15 minutes (pasteurization); then place the juice in an irradiation sterilization tank and treat it with an irradiation dose of 3 kGy for 15 minutes (irradiation sterilization).

[0085] Performance testing:

[0086] 1. Vitamin C content:

[0087] Determination of vitamin C content: According to GB 5009.86-2016, 2,6-dichloroindophenol titration method was used. The experimental results are shown in Table 2.

[0088] 2. Determination of total phenols:

[0089] Take 1mL of sample and dilute to 100mL, draw 1mL of diluent into a test tube, add 1mL of 1mol / L Folin-phenol reagent, shake thoroughly, let stand for 3-4min, add 5mL of 5g / 100mL Na2CO3 solution, shake well, react in a light-proof 50℃ water bath for 30min, and measure the absorbance at a wavelength of 765nm. The total phenol content is characterized by the gallic acid equivalent contained in each 100g sample, and the unit is mg / 100g. The experimental results are shown in Table 2.

[0090] 3. Browning index determination method:

[0091] Spectrophotometer method: The degree of browning is evaluated by measuring the absorbance of the sample at a specific wavelength. After the finished product is centrifuged at 4000r / min for 15min, the supernatant is taken, 5mL of the supernatant of the roxburghii juice is mixed with 5mL of distilled water in equal volumes, and the absorbance is measured at a wavelength of 420nm. The magnitude of the absorbance directly indicates the degree of browning, which is generally characterized by absorbance. The larger the absorbance value, the higher the degree of browning. The experimental results are shown in Table 2.

[0092] 4. Colony count during 5 months of storage:

[0093] Detection method: Determination of total colony count: Count the total number of microbial colonies in juice samples according to the relevant operations of GB4789.2 "National Food Safety Standard for Microbiological Examination of Foods - Determination of Total Colony Count". Determination of yeast and mold count: Count the yeast and mold in juice samples according to the relevant operations of GB4789.15 "National Food Safety Standard for Microbiological Examination of Foods - Count of Molds and Yeasts". The experimental results are shown in Table 2.

[0094] Table 2. List of test results of vitamin C content, total phenol content, total phenol content and colony count during 5 months of storage of finished products obtained by the method for controlling juice browning of Examples 1-13 and Comparative Examples 1-4

[0095]

[0096] a: The degree of browning is characterized by the absorbance value. The larger the absorbance value, the higher the degree of browning.

[0097] Under the conditions of vacuum ultrasonic and high-pressure CO2 combined sterilization, the degree of destruction of vitamin C is the lowest. This is because vitamin C is extremely sensitive to heat, and the pasteurization temperature can easily affect the stability of vitamin C. In addition, irradiation sterilization may change the molecular structure of food and is not suitable for foods with high water content, affecting the stability of active substances. After ultrasonic treatment of sea buckthorn juice, the content of dissolved oxygen in the juice is reduced, and the degree of oxidative degradation of ascorbic acid is reduced; on the other hand, during the high-pressure CO2 joint treatment process, polysaccharides and phenolic compounds are partially degraded, which also alleviates the degradation of ascorbic acid to a certain extent.

[0098] Phenolic substances are the main nutrients of fruits and vegetables, and play an important role in the color and taste of fruits and vegetables. The results show that the effects of vacuum ultrasound and high-pressure CO2 combined sterilization treatment on total phenol content are significantly different. Because low-temperature treatment will not destroy the corresponding covalent bonds in the roxburghii juice, it helps to retain the phenolic substances in the roxburghii juice. And the results in Table 2 show that the total phenol content data of the method proposed by the present invention is slightly higher than that of the control group, which may be due to the release of intracellular compounds by ultrasound, thereby increasing the bioactive substances.

[0099] The combined sterilization treatment of vacuum ultrasound and high-pressure CO2 has the lowest effect on the browning degree, indicating that the treatment method of the present invention is beneficial to avoiding protein denaturation and oxidative decomposition of VC and phenolic substances caused by thermal effects, and can better inhibit browning.

[0100] The total number of microbial colonies, molds and yeasts under different sterilization treatments within a storage period of 5 months at 25°C are shown in the table above. When microorganisms are detected by pasteurization and irradiation sterilization, vacuum ultrasound and high-pressure CO2 indicate that the treatment conditions in the present invention can not only effectively kill microorganisms, but also prevent sublethal microorganisms from reviving during the 5-month storage period, thereby effectively ensuring the quality and shelf life of the juice.

[0101] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for regulating juice browning by vacuum ultrasound-high pressure CO2, characterized in that: The method comprises the following preparation steps: Enzymolysis: adding a mixed enzyme preparation to the juice for enzymolysis treatment, subjecting the juice to ultrasonic treatment, with a maximum ultrasonic pressure range of 400-500 kPa / min, and stirring and homogenizing at a low speed to obtain an enzymolysis solution, wherein the temperature range of the enzymolysis solution is 30-42°C; Enzyme inactivation and sterilization: After the enzymatic hydrolyzate is homogenized by vacuum ultrasonic wave, high-pressure carbon dioxide gas is introduced into the solution for high-pressure sterilization, and the pressure is maintained at 4-8 MPa. The temperature of the juice is 10-40° C. to obtain the finished product.

2. The method for controlling juice browning by vacuum ultrasound-high pressure CO2 according to claim 1, characterized in that: The stirring speed in the enzymatic hydrolysis step is 150-200 r / min, and the stirring homogenization time is 30-50 min.

3. The method for controlling juice browning by vacuum ultrasound-high pressure CO2 according to claim 1, characterized in that: The maximum ultrasonic action time is 30-60 minutes.

4. The method for controlling juice browning by vacuum ultrasound-high pressure CO2 according to claim 1, characterized in that: The mixed enzyme preparation used in the enzymolysis step includes a combination of one or more of pectinesterase, cellulase, and alcohol dehydrogenase; the enzymolysis time is 30-60 minutes, and the concentration of the mixed enzyme preparation in the juice is 0.3-0.5 mg / mL.

5. The method for controlling juice browning by vacuum ultrasound-high pressure CO2 according to claim 4, characterized in that: The mixed enzyme preparation used in the enzymatic hydrolysis step is pectin esterase and cellulase in a mass ratio of (1-2):

2.

6. The method for controlling juice browning by vacuum ultrasound-high pressure CO2 according to claim 4, characterized in that: The mixed enzyme preparation used in the enzymatic hydrolysis step is pectin esterase, cellulase, and alcohol dehydrogenase in a mass ratio of 2:2:(0.3-1.5).

7. The method for controlling juice browning by vacuum ultrasound-high pressure CO2 according to claim 1, characterized in that: The high pressure sterilization time in the enzyme inactivation and sterilization step is maintained for 3-10 minutes.

8. The method for controlling juice browning by vacuum ultrasound-high pressure CO2 combination according to claim 1, characterized in that: The pressure in the enzyme inactivation and sterilization step is 7-8 MPa; the temperature of the juice in the enzyme inactivation and sterilization step is 30-40°C.

9. The method for controlling juice browning by vacuum ultrasound-high pressure CO2 according to claim 8, characterized in that: In the enzyme inactivation and sterilization step, the enzymatic solution is stirred at a speed of 150-200 r / min.

10. A control system for regulating browning of juice, characterized in that: Applicable to the method for jointly regulating juice browning by vacuum ultrasound and high pressure CO2 as described in any one of claims 1 to 9; The control system includes A sealed jar with a stirrer, An ultrasonic transducer connected to a sealed tank for ultrasonically vibrating the liquid in the sealed tank. Pipeline, The carbon dioxide storage tank is connected to the sealed tank through a pipeline. A control valve installed on the pipeline to control the opening and closing of the pipeline. A low-temperature cooling tank installed on the pipeline to cool the carbon dioxide in the pipeline. and a booster pump arranged on the pipeline for increasing the pressure of carbon dioxide.

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